The present invention relates to an improvement technology over solenoid control valves as prior art. The solenoid control valve as a first prior art is shown in FIG. 3. FIG. 3 represents a relative art of the present invention which is used as a solenoid control valve for a compressor or the like.
In FIG. 3, a valve portion 130 given in the lower part of the figure and a solenoid portion 101 are connected with each other by fitting the outer diameter surface on the upper side of a casing main body 103 to a mount borehole, which is located at the lower end of the casing main body 103 of the solenoid portion 101. And the solenoid portion 101 is assembled to a connector 105 by fitting the base portion 105A of the connector 105 to an engagement surface 103B and an end tip bottom surface portion 103C which form a step shoulder at the upper side of the casing main body 103. This base portion 105A tends to be long because of necessity of having an O-ring groove on outer diameter surface thereof. Moreover, in order to securely mount the casing main body 103 to the base portion 105A which is made of easily deflectable resin material, the base portion 105A needs to be formed in a long, cylindrical design. The O-ring groove receives O-ring 120 thereat. This O-ring 120 prevents water or the like from breaking from outside into a solenoid coil 104 side. The base portion 105A has a mount portion 105B and an anti-rotation lock portion 105F. The mount portion 105B is securely fixed by means of an end portion 103A of the casing main body 103 as well as the end tip bottom surface 103C which is stopped by one end surface 105D. Also there is a borehole disposed within the one end surface 105D side of the connector 105. This borehole integrally mounts an upper plate 106 which has a flange 106A. Also a through hole of the upper plate 106 fittingly receives the outer diameter surface on a sleeve 117 at its one end. Further, the other end portion of the sleeve 117 is fitted to the inner circumferential surface of the casing main body 105.
There is a fixed iron core 115 fitted to the inner diameter surface on the sleeve 117. A moveable iron core 110 which is freely slidable relative to the inner diameter surface of the sleeve 117 is arranged in such a manner that tapered contact surface thereof faces against the tapered receiving surface on the fixed iron core 115. A spring which is disposed in a borehole of the fixed iron core 115 at between the fixed iron core 115 and the moveable iron core 110 provides an urging force to the fixed iron core 115 and moveable iron core 110 in mutually opposite directions. The moveable iron core which is connected with one end of a solenoid rod 107 drives an action valve which is not shown in the figure. There is a solenoid coil 104 disposed outside of the periphery of the fixed iron core 115 and moveable iron core 110, which generates a magnetic field via sleeve 117. Also the solenoid coil 104 is fitted to the inner diameter surface 103D on the casing main body 103. A reference numeral 125 represents a snap ring for fastening the connector terminal of the connector 105.
There exists a solenoid control valve as a second prior art relative to the present invention [Japanese Patent Laid-open Publication No. 2001-59581 (FIG. 1), for example]. Arrangement of the mount portion of the connector and the casing main body in the second prior art is similar to FIG. 3, thus its figure is omitted. In this solenoid control valve, a connector's cap and a housing corresponding to a casing main body are connected into one-piece at the outer circumferential side of the two solenoid coils arranged in tandem, just like the way the valve portion is arranged. And the end portion of the housing is securely clinched to the end tip outer circumferential surface of the cap. Also this connector tends to become complex in structure because of necessary deposition of an intermediate ring in order that the connector and the housing may be press formed in one-piece. The press forming of the housing in one-piece increases its fabrication cost.
There also is another solenoid valve as a third prior art relative to the present invention [Published Patent Application 2001-82624 (FIG. 1), for example]. Arrangement of the mount portion of the resin-made connector and the casing main body in the third prior art is similar to FIG. 3, thus its figure is omitted. In this solenoid valve, a cylindrical portion of a connector is fittingly mounted to the outer periphery of the solenoid coil in a solenoid portion which is placed in a longitudinal direction just like the way the valve portion is placed. A casing main body is then fitted to the outer circumference on the cylindrical portion. In order that the cylindrical portion of the connector may be securely retained by the solenoid portion, an upper plate which is integral to the cylindrical portion of the connector is fittingly engaged to the casing main body. Because the cylindrical portion of the connector and the casing main body are merely kept in a fitting relation, thermal expansion of the resin-made connector may cause water to break into between the two members. Forming the connector and the casing main body in one-piece necessarily makes the structure more complex, and thereby its manufacture cost is increased.
Among the solenoid portions arranged as described above, as for the related art 1, the O-ring 120 is disposed for preventing water from breaking into the solenoid coil 104 side. Therefore, an O-ring groove which is formed on the base portion 105A and an O-ring 120 being disposed in the O-ring groove necessitate a further longitudinal extension of the base portion 105A of the connector 105 toward the valve portion 130 side. This may impose a problem on the solenoid control valve when it is to be installed in an apparatus requiring downsizing. Also clinching the casing main body 103 to the mount portion 105B of the connector 105 by inflecting the end portion 103A of the casing main body 103 may result in a creation of a gap at between the end portion 103A and the mount portion 105B due to the spring back induced in the connector 105 in accordance with elasticity of the resin material for the connector 105. Moreover, inflecting the end portion 103A in almost a right angle according to the mount portion 105B may cause a peeling of the plating on the inflected portion. The peeling off on the end portion 103A leads to a formation of rust on the end portion 103A. When the rust on the end portion 103A grows and reaches the O-ring, seal performance of the O-ring is deteriorated. To make matters worse, the O-ring is degradated and water is prone to breaking into the solenoid coil 104 side.
Next, as for the related art 2, its structure is still complex as the cylindrical portion of the connector is formed to surround the entire solenoid coil. The end portion of a casing main body (housing) fitting with the cylindrical portion is clinched to the end tip outer circumference in order to integrate the two members. There is, however, no seal provided thereat so that there remains a danger of water breaking into the solenoid coil side from the clinching portion. In particular, when a casing main body or connector cap is treated with plating for anti-corrosion purpose, inflection for the clinching may cause peeling off of the plated portion. Such a plate peeling may induce a further growth of corrosion at the clinching portion and allow water therefrom to break into the solenoid coil side.
Moreover, in the related art 3, structure thereof is yet complex as the cylindrical portion of the connector is also formed to surround the entire solenoid coil. Although the casing main body is fitted to an upper plate or the cylindrical portion of a connector, the two members are fixed to each other only under a fitting friction, and therefore sealing ability at between the casing main body and the upper plate or the cylindrical portion of a connector is weak such that water may break into the solenoid coil side from between the fitting surfaces.
The present invention is introduced to alleviate the above mentioned problems. A primary technical goal which this invention tries to achieve is to prevent water from breaking through the contact surfaces of the connector and the casing into the solenoid coil side. Another goal is to enhance electric conductivity by bringing the upper plate into a seal-tight contact against the casing main body. Yet another goal is to promote downsizing of the connector and to enable it to be mounted even in a small installation space of an application apparatus, which is expected to expand the applicability of the solenoid control valve.